Electromagnetic wave absorber is critical for reducing increasingly serious electromagnetic wave pollu-tion,however,the development of lightweight and broadband microwave absorbers remains a pressing challenge.We report here the rational design and synthesis of N-doped Ni@SiO2/graphene composite con-structed from 3D interconnected porous graphene network and Ni@SiO2 core-shell architecture,which fulfills lightweight and broadband requirements while exhibiting highly efficient electromagnetic wave absorption.The porous graphene network,functioning both as lightweight support and dielectric medi-ator,was synthesized via NaCl template-assisted high-temperature calcination method.Upon uniformly attached with core-shell Ni@SiO2 on the surface,the resulting abundant heterogeneous interfaces con-structed by graphene-Ni and Ni-SiO2 strongly reinforce polarization loss.The presence of low dielectric SiO2 allows facile tuning of the complex permittivity of ternary composite by adjusting coating thick-ness to balance the attenuation ability and impedance matching.Moreover,further N-doping of graphene assists in the optimization of dielectric loss ability.Taking account of the advantages arising from the porous hierarchical architecture,multiple absorption centers and diverse interfaces,the lightweight com-posite exhibits an ultra-strong reflection loss(RL)value of-71.13 dB at 13.76 GHz with a thickness of 2.46 mm and broad effective absorption bandwidth of 7.04 GHz at a low filler content of 15 wt.％.More importantly,the effective absorption range covers 13.28 GHz(4.72-18 GHz)with the optimized thickness of 1.6-5 mm,representing 83％of the whole range of frequencies.Our results demonstrate that the novel 3D porous N-doped Ni@SiO2/graphene network with hierarchical architecture is a promising candidate for high-performance electromagnetic wave absorption.

Rui Guo;Qi Zheng;Lianjun Wang;Yuchi Fan;Wan Jiang

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,College of Materials Science and Engineering,Donghua University,Shanghai 201620,China;Engineering Research Center of Advanced Glasses Manufacturing Technology,Ministry of Education,Donghua University,Shanghai 201620,China;Institute of Functional Materials,Donghua University,Shanghai 201620,China

材料科学技术（英文版）

[1]Rui Guo;Qi Zheng;Lianjun Wang;Yuchi Fan;Wan Jiang-.Porous N-doped Ni@SiO2/graphene network:Three-dimensional hierarchical architecture for strong and broad electromagnetic wave absorption)[J].材料科学技术（英文版）,2022(11):108-117

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